1. Field of the Invention
The present invention relates generally to the art of burners and torches, and more particularly to a torch which may be used in recreational environments such as with patios, decks or the like. Still more specifically, the present invention relates to a torch including a gas burner having gas flow and air control for producing a visible, stable flame.
2. Description of the Prior Art
Many types of torches and burners are known for mixing air and gas to produce a flame for a variety of applications such as welding, cooking, illumination and the like. For some applications, a visible flame is desired, independent of the heat output of the flame.
An example of the latter is the Olympic Torch. To produce such flames, less air is typically used than for heating burners, resulting in a cooler, but more visible, yellow flame. However, when such torches are employed outside, they tend to extinguish in adverse weather conditions, such as with high winds. An example of an application in which the problem is particularly pronounced is with the small, hand-held Olympic Torches carried by runners across the United States in 1996 before the Olympic Games in Atlanta. Torches with gas cylinders were used for such application. The initial "burner design" for the Olympic Torch included a complex and expensive secondary burner arrangement prepared from copper tubing, with multiple precisely defined orifices, coiled around a primary burner. This proposed Olympic relay torch is illustrated in a drawing dated Jun. 6, 1995 and submitted to the United States Patent and Trademark Office with this application. The burner was prepared on behalf of the Atlanta Committee for the Olympic Games by the College of Industrial Design and Architecture of the Georgia Institute of Technology.
While this burner provided an efficient torch and achieved the purpose intended, the product was quite expensive and ill-suited for use in recreational applications where both reliability and low cost are required.
One solution recently proposed by the inventors of the present application is described in greater detail later. This torch used a burner which included a gas inlet with gas-flow control and a primary air hole located in the vicinity of a gas orifice. The design also included a sintered filter flame holder, an inner cup, and an outer cup with inner cup air holes for flame stability. In addition, a wire mesh flame holder mounted on the inner cup also helped to keep the flame lit. This design was useful and represented a significantly less complex design but still did not meet the low cost and manufacturability requirements demanded by the mass retail market.
A burner which is low in manufacturing costs, reliable, attractive and which produces a stable, visible flame over an extended period of time would be a significant improvement in the art.
While torches using bottled gas as the fuel supply are known, as indicated above, the present inventors are not aware of any attempt to use a gas cylinder in a recreational patio or deck torch in which the cylinder may be supported above the ground, a deck or a table top. Although liquid fuel patio or deck burners have become increasingly common in recent years, they are relatively more difficult to use because they require periodic refilling and wick maintenance. A torch which could be used in a patio or deck environment, or for similar applications, and which employs a replaceable cylinder of fuel gas, rather than liquid fuel, would also represent an advance in this art.
Furthermore, citronella has been added to a wide variety of products in recent years, including candles, fuel oils, insect sprays and the like. While there is some debate as to the effectiveness of citronella as an insect repellent, some people believe that it is at least partly effective in reducing insects in the area in which the citronella product is used. In addition, citronella has a characteristic smell which many find to be pleasing. To date, and to the knowledge of the present inventors, no one has prepared a mixture of citronella oil and fuel gas in gas cylinders. The addition of citronella oil to propane or other gases in a gas cylinder would result in yet a further advance in this art.